Interpretive Summary: The microbial ecosystem of the intestinal tract of food animals is a natural resource that can be harnessed to exclude pathogenic bacteria such as Salmonella. Prebiotics are compounds that can be fed to food animals that are not digestible by the host animal but do provide a food source to the microbial populations of the gut. By feeding the microbial ecosystem specifically, we can target improving bacterial diversity and ability to exclude foodborne pathogenic bacteria. In this review, we discuss how prebiotics select for a microbial population hostile to pathogens and how these can be used in the future.

Technical Abstract:
Animals can be seriously impacted by bacterial pathogens that affect their growth efficiency and overall health, as well as food safety of animal-derived products. Some pathogenic bacteria, such as Salmonella, can be a shared problem for both human and animal health and can be found in many animal species. A fully mature ecosystem (the intestinal tract) occupies all environmental niches and utilizes nearly all available nutrients, which tends to exclude pathogenic bacteria from the complex gastrointestinal microbial population. Utilization of this native or artificially introduced microflora population to improve animal health and productivity has been termed a "probiotic," or competitive enhancement strategy. Advantages of harnessing the natural microbial ecosystem against the pathogens include ease of application and low economic and labor costs, and the use of a native microbial population to reduce transient pathogens is seen as a "natural" strategy. In this review, we will focus on the use of prebiotics and discuss the theory behind these compounds and their benefits and challenges for future implementation in food animals.